The proposed research investigates the neural mechanisms controlling breathing in anesthetized animals and in patients with airway obstruction during sleep (UAO). Investigations of the mechanisms of respiratory rhythmogenesis focus on identifying cells of the rostral ventro-lateral group of the medulla that appear to process the inspiratory inhibitory input from the rostral pons. Recordings in the nucleus of the tractus solitarius examine the interaction between functionally identified respiratory neurons using correlational methods applied to two spike trains recorded on electrodes placed in the same cluster of respiratory neurons. The pathogenesis of periodic oropharyngeal occlusion during sleep will be explored using EMG's of the genioglossus and tensor palatini. Changes in the activity of these muscles will be correlated with naso-pharyngeal resistance while awake and asleep. We have discovered that strychnine ameliorates UAO and the proposed research will evaluate its efficacy in this disorder. EMG studies are proposed to elucidate the mechanism of action of the drug.